Pre and Post Update Testing

Samsung launched their 840 Series SSDs back in May of 2013, which is over three years ago as of this writing. They were well-received as a budget unit but rapidly eclipsed by the follow-on release of the 840 EVO.

A quick check of our test 840 revealed inconsistent read speeds.

We broke news of Samsung’s TLC SSDs being effected by a time-based degrading of read speeds in September of 2014, and since then we have seen nearly every affected product patched by Samsung, with one glaring exception - the original 840 SSD. While the 840 EVO was a TLC SSD with a built-in SLC static data cache, the preceding 840 was a pure TLC drive. With the focus being on the newer / more popular drives, I had done only spot-check testing of our base 840 sample here at the lab, but once I heard there was finally a patch for this unit, I set out to do some pre-update testing so that I could gauge any improvements to read speed from this update.

As a refresher, ‘stale’ data on an 840 EVO would see reduced read speeds over a period of months after those files were written to the drive. This issue was properly addressed in a firmware issued back in April of 2015, but there were continued grumbles from owners of other affected drives, namely the base model 840. With the Advanced Performance Optimization patch being issued so long after others have been patched, I’m left wondering why there was such a long delay on this one? Differences in the base-840’s demonstration of this issue revealed themselves in my pre-patch testing:

Introduction, Specifications and Packaging

Mid last year, Samsung introduced the 840 EVO. This was their evolutionary step from the 840 Pro, which had launched a year prior. While the Pro was a performance MLC SSD, the EVO was TLC, and for most typical proved just as speedy. The reason for this was Samsung’s inclusion of a small SLC cache on each TLC die. Dubbed TurboWrite, this write-back cache gave the EVO the best write performance of any TLC-based SSD on the market. Samsung had also introduced a DRAM cache based RAPID mode - included with their Magician value added software solution. The EVO was among the top selling SSDs since its launch, despite a small hiccupquickly corrected by Samsung.

Fast forward to June of this year where we saw the 850 Pro. Having tested the waters with 24-layer 3D VNAND, Samsung revises this design, increasing the layer count to 32 and reducing the die capacity from 128Gbit to 86Gbit. The smaller die capacity enables a 50% performance gain, stacked on top of the 100% write speed gain accomplished by the reduced cross talk of the 3D VNAND architecture. These changes did great things for the performance of the 850 Pro, especially in the lower capacities. While competing 120/128GB SSDs were typically limited to 150 MB/sec write speeds, the 128GB 850 Pro cruises along at over 3x that speed, nearly saturating the SATA interface. The performance might have been great, but so was the cost - 850 Pro’s have stuck around $0.70/GB since their launch, forcing budget conscious upgraders to seek competing solutions. What we needed was an 850 EVO, and now I can happily say here it is:

As the 840 EVO was a pretty big deal, I believe the 850 EVO has an equal chance of success, so instead of going for a capacity roundup, this first piece will cover the 120GB and 500GB capacities. A surprising number of our readers run a pair of smaller capacity 840 EVOs in a RAID, so we will be testing a matched pair of 850 EVOs in RAID-0. To demonstrate the transparent performance boosting of RAPID, I’ll also run both capacities through our full test suite with RAPID mode enabled. There is lots of testing to get through, so let’s get cracking!

While at Storage Visions, I had a quick word with Chris Geiser of Samsung. Over the past few weeks there have been updates to 840 (PRO / EVO) SSD Firmware as well as to their SSD Magician software. These updates enable increased performance as well as full drive encryption (with no performance loss whatsoever). Check out the video below for full details:

So long story short, if you own these drives, consider updating your Magician Software, SSD firmware, and start protecting your data with full drive encryption. As always with any firmware upgrade, even though Samsung updates are non-destructive, it's a good idea to back up first regardless.